This invention relates to a drive assembly for a rolling door that opens and closes an opening of a building such as an office building or factory.
A drive assembly for the rolling door such as an architectural shutter generally comprises components including driving means such as an electric motor or a manually driving device, a speed reducer, and a brake mechanism for preventing a rotation of an output shaft that might include a motor shaft.
The drive assembly should be protected by a casing so as not to be damaged by contacting other members at the time of installation of the drive assembly. Thus, as shown in FIG. 13, each component constituting the drive assembly is individually covered by a casing C and is installed one by one with fastening means such as a bolt. According to this configuration, the installation of components is bothersome and complicated, and the number of members constituting the drive assembly increases because each casing accommodating each member should be required.
Japanese Utility Model publication No.5- 35997 discloses a cylindrical casing which houses members constituting the drive assembly. According to this casing, an electric motor of the drive assembly includes a bare stator core that should be fixed to the casing. To fix the stator core to the casing, the cylindrical casing is heated to increase an internal diameter, and the components including the electric motor are inserted to the casing in the expanded state. Then the casing is cooled to room temperature to reduce the internal diameter so that those components are fixed inside the casing. According to this method, heating equipment is required and the components must be installed in the casing quickly before the heated casing is cooled.
Further, when installing the components into the cylindrical casing having a circular internal surface, if the assembly includes a reduction gear that transmits a driving force from a motor shaft of the electric motor to an output shaft for example, the positioning of the reduction gear and the output shaft must be properly and precisely done and the positioned components must be inserted into the heated casing.
An object of the present invention is to preclude those disadvantages.
There is provided a drive assembly for opening and closing a rolling door that comprises a cylindrical casing accommodating drive assembly components. The casing has spaced apart opposed edge portions to define a gap therebetween to form a gap portion in a natural state in which the natural state means a state without applying any external forces. The drive assembly includes fastening means for narrowing the gap between the opposed edge portions such that the drive assembly components are aligned and fixed inside the casing by fastening the gap portion.
This construction precludes the bothersome operation that includes heating the casing to expand the diameter and inserting the components to the heated casing. Further, this construction permits fixing drive assembly components without looseness. Preferably, the gap portion provided in the casing extends in an orthogonal direction to the radial direction of the casing.
The casing may be comprised of a pair of semi-cylindrical parts having opposed edge portions. One opposed the edge portions constitute engaging portions that are detachably engaged to each other. The other opposed edge portions constitute the gap portion in the natural state in which the engaging portions are engaged.
The opposed edge portions defining the gap portion may have flanges extending outwardly in the radial direction, and the fastening means for narrowing the gap portion is provided in the flanges.
The drive assembly may be comprised of a plurality of units that have substantially the same outer diameter as an inner diameter of the casing. Each shaft is automatically centralized when a first bracket and a second bracket are fixed to the casing. The units are engaged to each other and installed in the casing.
The assembly may include a unit that constitutes a gear portion reducing a motor driving force and outputting a force. The unit comprises a motor shaft, a gear shaft having a reduction gear, an output shaft, a first bracket which journals the motor shaft and one end of the gear shaft, and a second bracket which journals the output shaft and the other end of the gear shaft. An external diameter of the both brackets is substantially the same as the internal diameter of the casing. The motor shaft, the gear shaft and the driving shaft are aligned and centralized by reducing the diameter of the casing. Each shaft is automatically aligned when a first bracket and a second bracket are fixed to the casing.
The first and the second brackets may have protruding portions in outer surfaces and the casing may have a groove engaging the protruding portions. The first and the second brackets are temporarily positioned by the engagement of the protruding portions and the groove, and shafts are to be aligned by reducing the diameter of the casing.